| Description: | Measured values of downwelling hemispheric shortwave radiation were up to 40 W/m^2 higher
than derived values during the afternoon hours.
Analysis reveals that this is likely an artifact of the cosine response of the particular
installed PSP coupled with typical uncertainties of this set of installed radiometers.
That is, this particular instrument cluster seems to be producing cumulative errors on
the high side of accepted values.
The PSP contains the most uncertainty in measurement at this station. Users should use a
derived value for the downwelling shortwave hemispheric irradiance (DS). Where DS =
diffuse component + direct normal * cos(SZA) component described in the SIRS handbook Sec 7.2
available at: http://www.arm.gov/publications/tech_reports/handbooks/sirs_handbook.pdf |